Nails? LOL You could also get some industrial strength, construction quality adhesive. It really depends on the type of materials that you are dealing with (cabinet and wall), size and weight, moisture levels etc. Lowe's or Home Depot should have something or be able to recommend a solution. Hope this helps.
Cleats,Molly bolts,Brackets Why? are they stripped? Nothing to screw into? What are walls made of? What is cabinet made of?