No. Pokemon with Toxic will ruin your Cosmic Power setup. Cosmic Power is viable with Pokemon that have Magic Guard, like Clefable and Sigilyph.
May I suggest a Hazards Deoxys-D?
Deoxys-D @ Leftovers
Trait: Pressure
EVs: 252 HP / 4 SDef / 252 Spd
Timid Nature (+spd, -Atk)
- Stealth Rock
- Spikes
- Night Shade
- Recover
