I'm traveling to Nepal and I don't know if I need to bring power adapters and if so which power adapters to bring
Depends on which plugs you have. The type H, which is the three sort of flat pins in a V shape, will need an adapter. The type M the three round pins will work in some outlets.
Unfortunately Nepal uses several different sockets, so might be good to have an adapter to type C, the two round pin plug used in Europe.