Preheat the oven to 425°F and line a baking sheet with parchment paper.
In a shallow bowl, mix the panko breadcrumbs, grated Parmesan, Italian seasoning, garlic powder, salt, and pepper.
In a second bowl, beat the eggs until smooth.
Dip each chicken breast in the egg, then press it into the breadcrumb mixture until fully coated on both sides.
Place the breaded chicken on the prepared baking sheet and bake for 20 to 25 minutes until the coating is golden and the chicken reaches 165°F inside.
While the chicken bakes, cook the spaghetti in a large pot of salted boiling water according to package directions, then drain.
Warm the marinara sauce in a small saucepan over low heat.
Top each baked chicken breast with ¼ cup marinara and ¼ cup mozzarella, then return to the oven for 3 to 5 minutes until the cheese melts.
Serve the chicken over the spaghetti with the remaining marinara spooned on top and fresh basil scattered over everything.