Preheat your oven to 400°F and line a baking sheet with parchment paper.
In a blender or food processor, combine the chicken breast, egg white, dried basil, salt, and pepper. Blend until a smooth, thick batter forms, which will serve as the pizza crust.
Spread the chicken mixture evenly on the prepared baking sheet, shaping it into a round or rectangular crust about 1/4 to 1/2 inch thick.
Bake the chicken crust in the oven for about 15 minutes, or until it is fully cooked and just starting to firm up.
Remove the crust from the oven and spread the tomato sauce evenly over its surface. Top with diced red bell pepper, red onion, and spinach.
Sprinkle the part-skim mozzarella cheese over the vegetables.
Return the pizza to the oven and bake for an additional 5-7 minutes, or until the cheese has melted and the vegetables are slightly roasted.
Remove from the oven, let cool slightly, and then slice and serve. Enjoy your nutritious, protein-packed pizza!