well, if you don't want your GC then you can be honest and tell them that you're quitting I guess..or you can go to Nepal after receiving your gc may be you want to come back if it doesn't work out in Nepal but if you have made up your mind to live rest of your life in Nepal then why bother with GC just tell them to stop the process and save their time and yours

When your actions are in coherence with your inner desires, be confident that you are moving towards greater joy in life. The propensity of the human mind is to seek happiness. You have made a decision that many Nepalis in the US find difficult to make. Live your dream; after-all America is a dream and Nepal is also a dream! In this network of dreams, we meet different people and objects, and get attached to it thinking objects and ideas have independent reality. However, dreams, dream-objects, and the dreamer are all pure consciousness. In this vast space of consciousness lies Nepal and America just like a flash of lightening! You are merely a witness consciousness witnessing all the happenings of this cosmic phenomenons. Do what is right and appropriate. Be kind and compassionate. Time will surely reveal all the colors of the petals and the fragrance that lies hidden inside the seed. May you be liberated !