Preheat oven to 450°F. Line a baking sheet with aluminum foil and coat with cooking spray.

Put walnuts in a heavy duty re-sealable plastic bag. Close bag. Use a rolling pin to crush nuts into fine pieces. Add crumbs, rosemary, garlic powder, salt and pepper.

Lightly beat egg in a shallow dish. Place half the chicken strips into egg and turn to coat. Lift chicken strips with tongs or fork, letting excess egg drain off; put into bag with crumbs. Close bag. Gently shake bag and press walnuts onto chicken.

Use tongs to remove chicken from bag and place on prepared pan, leaving space between pieces. Repeat dipping and coating procedure with remaining chicken. Bake 8 to 10 minutes until golden brown and cooked through (170°F).

Meanwhile, combine marinara and red pepper in a small saucepan or microwave-safe dish. Heat just until warm. Serve over chicken strips.