Preheat oven to 350 F. Line two cookie sheets with parchment paper and set aside.
Combine flour, baking soda, and salt in a medium bowl and set aside. In another bowl or the bowl of a stand mixer, beat the butter and sugars together at medium speed until fluffy, about two minutes. Add egg and vanilla and beat until well combined, about 1 minute. Add the flour mixture and beat well. Add oats and beat to combine. Stir in pecans and chocolate chips.
Drop dough onto cookie sheets in rounded tablespoonfuls. Bake for 10-12 minutes. Cool on cookie sheets for ten minutes, then remove to racks to cool completely.
Recipe by Baked In at https://www.baked-in.com/2012/03/31/oatmeal-chocolate-chip-pecan-cookies/