Preheat the oven to 350 degrees Fahrenheit. Line tw0 large, rimmed baking sheets with parchment paper or silicone mats for easy clean-up.
In a large mixing bowl, combine the peanut butter with the sugar and coconut oil. Use an electric mixer or a large spoon to mix until well combined. Add the eggs, baking soda and vanilla, and mix well. Add the oats and chocolate chips and mix until they’re evenly incorporated.
Working with an ice cream scoop or ¼ cup measuring cup, drop the cookies onto the prepared baking sheets. These cookies spread while baking, so leave several inches around each (I can bake six at a time). If they are irregularly shaped at the base, gently shape them into a more rounded mound. If you’d like your cookies to look extra pretty, dot a few extra M&M’s and chocolate chips on each mound of dough before baking.
Bake 10 to 12 minutes, until they’re just starting to turn golden around the edges. Do not overbake. Let the cookies cool for 10 minutes before transferring to a cooling rack. In the meantime, bake your next six cookies, and so on.
If desired, sprinkle the cookies lightly with flaky sea salt. Let them cool completely before storing them in an airtight container. Cookies will keep well for several days at room temperature.