I do not think you can apply yourself (unless it is one of those NIW cases). A lawyer can start the process on behalf of your employer where you will be the beneficiary. An experienced lawyer would be likely to have a good idea about the prevailing wages for the location and the job. If your wage does not qualify for EB2, you could also do EB3. I think for Nepal, the processing time is same for both EB2 and EB3.

That's right. Hire Professional Lawyer and he/she will guide you the process of filing GC through EB2 or EB3 (both are current) for Nepal. Prevailing wage depends on the job deskription that should match with your experience and skills, experience and location.