(Don't forget that this is Switch = KO, so U-Turn removes Taunt and should force Chimecho to use Taunt again A2 followed by Wrap. Also, I believe Neville starts with 120 HP, not 100.)
Time for the finale, Neville!
Rapid Spin -> Bite -> Crunch
If CHIMECHO THE TERRIBLE uses a damaging Normal-type combo, change that action to Fake Out
If CHIMECHO THE TERRIBLE uses Endure, lol