Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper or silicone baking mats.
In a medium bowl, whisk together the flour, rolled oats, baking soda, and salt. Set aside.
In a large mixing bowl, cream together the softened butter, granulated sugar, and brown sugar using an electric mixer on medium speed for 3-4 minutes until light and fluffy.
Add eggs one at a time to the butter mixture, beating well after each addition. Mix in the vanilla extract until well combined.
Gradually add the dry ingredient mixture to the wet ingredients, mixing on low speed just until combined. Do not overmix.
Using a wooden spoon or sturdy spatula, fold in the chocolate chips, chopped pecans, shredded coconut, and M&Ms until evenly distributed throughout the dough.
Using a cookie scoop or spoon, portion the dough into balls about 2 tablespoons in size and place them about 2 inches apart on the prepared baking sheets.
Bake for 10-12 minutes, until the edges are golden brown but the centers still look slightly soft and underdone.
Remove from the oven and let cookies cool on the baking sheet for 5 minutes to set.
Transfer cookies to a wire cooling rack and allow to cool completely, about 20-30 minutes, to reach ideal chewy texture.
Store completely cooled cookies in an airtight container at room temperature for up to 7 days, or freeze for up to 3 months.
