SM NU has been deemed a pretty matchup-based tier for awhile now, for some because of Z-Moves and others because of certain Pokemon. Although the general consensus is that the tier is pretty alright as is, I (with backing from the other TLs) wanted to field opinions on three Pokemon that most frequently do get calls for action because of how limiting they are to teambuilding: Comfey, Sigilyph, and Scrafty.

Comfey needs no introduction. Its Triage ability is dumb and cringe and makes offensive counterplay irrelevant, and its coverage is all it needs and then some. Hidden Power gives it a level of versatility that can flip many matchups on their heads. If Comfey is Hidden Power Ground, then options like Delphox, Togedemaru, Steelix, and Garbodor become a ton less reliable at stopping it. If Hidden Power Psychic is chosen, then you can end up beating Weezing one-on-one and gain better angles against Victreebel and even Golbat; this also enables Comfey to run Grass Knot to retain a favorable Steelix matchup. Obviously, Comfey can't get all of these potential matchup wins in one set, and generally teams can fit multiple answers without going out of their way to do so, but we've seen time and time again Comfey bullshit its way to wins in matchups where it didn't look like it had the means to do so from team preview.

Sigilyph takes set versatility to a new level. From Life Orb to Choice Specs to random Z-Move setup sets, Sigilyph is impossible to get a read on from the start and has pretty limited counterplay overall. Generic special walls aren't the greatest because they either fall to its coverage moves or take too much from its STAB attacks, and some of the better answers---Delphox and Slowking come to mind---are Pursuit trappable. Meanwhile, there also exist sets like Cosmic Power + Flyinium Z, Z-Toxic, and even fucking Z-Miracle Eye that all add extra layers to what Sigilyph can do in a game to bypass defensive stops like Incineroar and Guzzlord to its setup sets. The few limiting factors to Sigilyph, i.e. it's Pursuit trappable itself and can somewhat be pivoted around if you predict it properly, aren't exactly damning to its overall success rate, and these negatives are possible to mitigate with Protect sets and good prediction.

Scrafty doesn't get the same amount of criticism as the first two mentions, but it's certainly something that you have to be cognizant of in the builder lest you risk being 6-0ed on the spot. Dragon Dance + Chople Berry sets make Passimian their bitch and can snowball out of control with relative ease if your opponent lacks one of the two viable Fairy-types in the format, and Bulk Up variants have a lot of leeway around the multitude of passive Pokemon like Seismitoad and Blastoise to set up multiple times a game. Compared to the other two Pokemon being brought up, Scrafty does have more available counterplay to it. Bulkier sets can be shut down with Taunt users like Weezing and Golbat, and Dragon Dance variants are a bit slow without a second boost still, which makes them easy enough to revenge kill with Pokemon like Whimsicott, Flyinium Z Aerodactyl, Comfey, and Passimian (if Scrafty opts for a Z-Crystal > Chople Berry).
Here's a tags list of SM NU players from the past couple tournaments that may want to give input:
Important: this is not a thread guaranteeing action on any of the above Pokemon. It's simply a means to get discussion started up to see if there's a route to take that's supported by players of the format.

Comfey needs no introduction. Its Triage ability is dumb and cringe and makes offensive counterplay irrelevant, and its coverage is all it needs and then some. Hidden Power gives it a level of versatility that can flip many matchups on their heads. If Comfey is Hidden Power Ground, then options like Delphox, Togedemaru, Steelix, and Garbodor become a ton less reliable at stopping it. If Hidden Power Psychic is chosen, then you can end up beating Weezing one-on-one and gain better angles against Victreebel and even Golbat; this also enables Comfey to run Grass Knot to retain a favorable Steelix matchup. Obviously, Comfey can't get all of these potential matchup wins in one set, and generally teams can fit multiple answers without going out of their way to do so, but we've seen time and time again Comfey bullshit its way to wins in matchups where it didn't look like it had the means to do so from team preview.

Sigilyph takes set versatility to a new level. From Life Orb to Choice Specs to random Z-Move setup sets, Sigilyph is impossible to get a read on from the start and has pretty limited counterplay overall. Generic special walls aren't the greatest because they either fall to its coverage moves or take too much from its STAB attacks, and some of the better answers---Delphox and Slowking come to mind---are Pursuit trappable. Meanwhile, there also exist sets like Cosmic Power + Flyinium Z, Z-Toxic, and even fucking Z-Miracle Eye that all add extra layers to what Sigilyph can do in a game to bypass defensive stops like Incineroar and Guzzlord to its setup sets. The few limiting factors to Sigilyph, i.e. it's Pursuit trappable itself and can somewhat be pivoted around if you predict it properly, aren't exactly damning to its overall success rate, and these negatives are possible to mitigate with Protect sets and good prediction.

Scrafty doesn't get the same amount of criticism as the first two mentions, but it's certainly something that you have to be cognizant of in the builder lest you risk being 6-0ed on the spot. Dragon Dance + Chople Berry sets make Passimian their bitch and can snowball out of control with relative ease if your opponent lacks one of the two viable Fairy-types in the format, and Bulk Up variants have a lot of leeway around the multitude of passive Pokemon like Seismitoad and Blastoise to set up multiple times a game. Compared to the other two Pokemon being brought up, Scrafty does have more available counterplay to it. Bulkier sets can be shut down with Taunt users like Weezing and Golbat, and Dragon Dance variants are a bit slow without a second boost still, which makes them easy enough to revenge kill with Pokemon like Whimsicott, Flyinium Z Aerodactyl, Comfey, and Passimian (if Scrafty opts for a Z-Crystal > Chople Berry).
Here's a tags list of SM NU players from the past couple tournaments that may want to give input:
Important: this is not a thread guaranteeing action on any of the above Pokemon. It's simply a means to get discussion started up to see if there's a route to take that's supported by players of the format.