Preheat oven to 425°F. Line a sheet pan with foil and spray the foil with olive oil spray.
Pat the 12 chicken tenders dry and sprinkle them evenly with 1 teaspoon kosher salt.
Beat 1 large egg in a shallow bowl.
Place the 1 cup seasoned breadcrumbs in a second shallow bowl and divide them into two equal portions: put 1/2 cup in the bowl for dredging and reserve the other 1/2 cup in a small bowl to use for tossing later.
Working one at a time, dip each chicken tender into the beaten egg, letting excess egg drip off, then press it into the 1/2 cup of breadcrumbs to coat. Shake off excess breadcrumbs and place the coated tenders in a single layer on the prepared sheet pan.
Transfer the coated tenders to a large bowl, add the reserved 1/2 cup breadcrumbs, and gently toss the tenders so they pick up the additional breadcrumbs; return the tenders to the sheet pan in a single layer.
Spray both sides of each breadcrumb-coated chicken tender generously with olive oil spray.
Bake on the sheet pan for 18 minutes, flipping the tenders once halfway through baking (about 9 minutes), until cooked through.
Transfer the baked tenders to a 9×13-inch baking pan and arrange them in a single layer.
Spread 1 1/2 cups marinara sauce evenly over the chicken tenders.
Sprinkle 1 cup shredded part-skim mozzarella over the sauce, then sprinkle 1/4 cup grated Parmesan cheese on top.
Bake in the oven for 8 to 10 minutes, until the marinara is hot and the cheeses are melted.
Remove from the oven and garnish with chopped basil leaves before serving.