Combine ground chicken, salt, pepper, garlic powder, Italian seasoning, and grated Parmesan in a bowl. Spread mixture in a thin layer over one side of each toast, being sure to reach the edges of the bread.
Heat a large nonstick skillet over medium-high heat. Add 2 teaspoons oil and place half of the toasts, chicken side down, in the hot skillet, lightly pressing down on each one with a spatula.
Cook, undisturbed, until golden brown and cooked through, about 4 minutes. Flip, turn heat to low, and top each toast with 1 tablespoon marinara sauce and 2 tablespoons mozzarella cheese. Cover the skillet and turn off the heat, and let stand until the cheese is completely melted, about 2 minutes. Repeat with remaining toasts.