What size breaker do I use for a 60 amp rated load?

60A. Or 80A depending on the application.

Not enough info.. Is it a motor or a hot tub sub panel?? But if it is a continuous load ( running 3 hrs or more at one time) it needs to be 125% of the load or in your case a 80A breaker rated for the use. ( usually types are HACR BR etc... ) But if it is a sub panel 60a or just a circuit requiring 60a that isn't used often it would be 60a