In gen 5 I used to run lead porygon-z with choice scarf and trick. It almost always caught the enemy off guard and worked in my favor. Sometimes I would trick my scarf onto a tyranitar setting up stealth rocks, Or I would grab someone's focus sash, take a hit from them with 1 hp left, and kill them with the next attack. And if tricking my item wasn't viable, I would just go for a tri-attack or a thunderbolt and it just tore teams apart.Would a Choiced Frisk Switcheroo set be viable? It's super fast, so it could easily get a Switcheroo off on a defensive Pokémon, although if the opponent guesses that and switches a MEvo out, or a Choiced Pokémon to absorb the Switcheroo, the surprise factor is kaputted, and Noivern could potentially be one-shot because its' fragility.
The reason I mention porygon-z at all is that they seem very similar when you run them as trick leads. The fact that noivern gets frisk is kind of incredible, now you can see if someone else is choiced before they even start attacking, or if they're doing some weird strategy you wouldn't have thought of. You can also play around with stuff like red cards and weakness policies too. I guess theres a little bit of risk vs Sp attackers, since if you switcheroo on an attack from them you're gone.
I've been running some calculations, and it seems like with a choice spec (since noi doesn't need any more speed than he already has, unlike pory), noivern is doing just about as much damage as porygon-z usually does, more if you start using draco meteor.