Preheat oven to 400 F degrees, and line a baking sheet with aluminum foil or parchment paper. Spread panko out into an even layer on baking sheet, spray lightly with cooking spray, and bake 3-4 minutes, until golden.
Set panko aside in large shallow bowl. Add oven safe wire rack to top of baking sheet, and set aside. Increase oven temperature to 450 F degrees. To bowl, add parsley, salt, pepper, smoked paprika, onion powder and garlic powder. Toss to combine well.
In another shallow bowl, add egg whites and splash of water. Beat lightly. Pat chicken tenders dry. Season chicken tenders with additional pinch of salt and pepper.
Add chicken tender to egg white mixture, turning to coat. Lift up, allowing excess egg whites to drip off, then add to panko bowl. Coat chicken tender with seasoned panko, then transfer to prepared wire rack/baking sheet. Repeat with remaining tenders.
Lightly spray chicken tenders with cooking spray if desired, then bake 12-15 minutes (depending on the size of the tenders), until golden brown and chicken is cooked through.