It would be "germs and disease" that had the greatest impact when the Old and New Worlds met, since the Natives in the New World were not immune to the germs that the Europeans were carrying--leading thousands of Natives to be killed.
Nepal is a secular state under the Constitution Of Nepal 2015, which was promulgated on 20 September 2015. The Constitution provides for freedom to practice one's religion. The Constitution also specifically denies the right to convert another person.