"This Pokémon's moves with extra effects have 1.3× their power, but lose their extra effects.
An effect chance is a move's
chance to inflict a status ailment, cause a stat change*, or make the target flinch in addition to the move's main effect. For example,
Thunder Shock's paralysis is an extra effect, but
Thunder Wave's is not, nor are
Knock Off's item removal and
Air Cutter's increased critical hit rate.
Moves that
lower the user's stats are unaffected."
*does not imply positive or negative
So in my mind that means Sheer Force boosts Rock Smash, Icy Wind, and Mud-Slap (since they would cause a stat change), Nuzzle (which has a chance to inflict a status ailment), and Astonish (chance to flinch.) Draco Meteor/Superpower/Power Up Punch raise/lower your own stats, so they don't count.
It's completely broken on Nidoking either way, who can abuse STAB Mud-Slap, STAB Poison Sting, STAB Bulldoze, Icy Wind, Water Pulse, Rock Smash, Confusion, and Rock Tomb, letting it go purely Physical now or run a viable mixed set.