Preheat the oven to 350 degrees F (175 degrees C).

Combine butter and coconut oil in a saucepan over medium-low heat; cook until melted, 2 to 3 minutes. Set aside to cool.

Mix 3/4 cup plus 1 tablespoon brown sugar, white sugar, eggs, and vanilla extract together in a mixing bowl.

Combine flour, baking soda, and salt in a separate bowl. Add to egg mixture, mixing well. Stir in oats and chocolate chips.

Roll heaping tablespoonfuls of cookie dough into balls. Place 2 inches apart on ungreased cookie sheets.

Bake in the preheated oven until edges are set, about 12 minutes. Cool on the cookie sheets for 2 minutes, then transfer to wire cooling racks.