Is grilled a noun

Yes, the Word 'grill' is both a noun (grill, grills) and a verb (grill, grills, grilling, grilled).

The noun grill is a singular, common, concrete noun; a Word for a flat frame of metal bars on which food can be placed and cooked over a fire; a restaurant that serves foods cooked on a grill; any metal framework that resembles a grill.