Mix seasoning together in a small zip top bag. Add 1 tablespoon seasoning blend, 1 cup buttermilk and chicken to a large freezer bag and marinate 6-24 hours.
Preheat oven to 400 degrees F. Line a rimmed baking tray with parchment paper. Add butter to baking tray and let melt in the oven while it preheats. Remove baking tray once butter is melted.
Mix together flour, panko, cornmeal and remaining spices in a large bowl. Add half of this breading mixture to a large freezer bag.
Remove chicken tenders from buttermilk and dab off excess marinade with paper towels.
Add half of the chicken to the breadcrumb bag and shake until well coated, pressing the breadcrumbs into the chicken with your fingers through the bag. Lay breaded chicken in butter on baking tray. Add remaining breadcrumb mixture to bag along with remaining chicken and repeat.
Bake at 400 degrees F for 10-12 minutes until golden then carefully flip chicken and bake another 5-6 minutes then broil to desired crispiness.