Preheat oven to 400°F (200°C)
Line a baking sheet with parchment paper
In a large bowl, combine ground chicken, egg, mozzarella, Parmesan, garlic powder, Italian seasoning, salt, and pepper
Mix until fully combined but do not overwork
Transfer mixture to prepared baking sheet
Press evenly into a round pizza shape about 1/4 inch thick
Bake until crust is firm and lightly golden
Remove from oven and carefully drain any excess moisture
Spread pizza sauce evenly over the crust
Sprinkle shredded mozzarella over the sauce
Add cherry tomatoes and red onion slices
Return to oven and bake until cheese is melted and bubbly
Remove from oven and let rest for a few minutes
Garnish with fresh basil before slicing