Khadka is a Nepalese Surname.... It depends on what king of KHADKA are u... The people of Nepal are predominately Tibeto-Mongolian but they speak Khas, a dialect of a northern Indic language. It mean that there ancestors are from there. These are some surnames that are predominately tibeto-mongolian.. Barati, Khadka,Nawang Topkay
Paneru, Tensing Norgay, Thakchay Duma Tshering.... It all depends on you ancestor.