Preheat oven to 350°F. Line 3 rimmed baking sheets with parchment paper.
Beat granulated sugar and butter in a large bowl with an electric mixer on medium speed until fluffy, 2 to 3 minutes, stopping to scrape down sides as needed. Add egg, banana, and maple syrup; beat on medium speed until combined, about 1 minute.
Whisk together all-purpose flour, whole-wheat flour, cinnamon, baking soda, and salt in a medium bowl. With mixer on low speed, gradually add flour mixture to sugar mixture, beating until nearly combined, about 45 seconds. Stir in oats, 1 cup pecans, ½ cup coconut, and ½ cup chocolate chips.
Divide dough into 18 mounds (about ¼ cup each) on prepared baking sheets, spacing 2 ½ inches apart. Press mounds to a ¾-inch thickness using damp hands. Sprinkle tops evenly with remaining ¼ cup each pecans, coconut, and chocolate chips; lightly press into dough.
Bake until edges are just set and centers are still slightly soft, 12 to 14 minutes. Let cool on baking sheets 5 minutes. Transfer to wire racks; let cool completely, about 30 minutes.