Adjust oven racks to upper-middle and lower-middle positions and heat oven to 350 degrees. Line 2 rimmed baking sheets with parchment paper. Whisk flour, oats, coconut, baking soda, baking powder, and salt together in bowl; set aside.

Using stand mixer fitted with paddle, beat butter, granulated sugar, and brown sugar on medium-high speed until pale and fluffy, about 3 minutes. Add egg and vanilla and beat until combined. Reduce speed to low, add flour mixture, and mix until combined, scraping down bowl as needed. Add cereal and chocolate chips and mix until just combined.

Working with 1 tablespoon dough at a time, roll into balls and evenly space on prepared sheets, 24 cookies per sheet. Using bottom of greased measuring cup, press dough balls into ½-inch-thick disks, about 1½ inches in diameter.

Bake until edges of cookies are just beginning to brown, 10 to 12 minutes, switching and rotating sheets halfway through baking. Let cookies cool on sheets for 5 minutes, then transfer to wire rack. Let cookies cool completely before serving. (Cooled cookies can be stored in zipper-lock bag at room temperature for up to 5 days.)