Preheat your oven to 350°F (175°C). This will ensure that your muffins bake evenly and rise beautifully.
Line a muffin tin with paper liners or grease it lightly with non-stick spray. This will help prevent the muffins from sticking.
In a large mixing bowl, whisk together the all-purpose flour, baking soda, and salt. This step is crucial for evenly distributing the leavening agent and ensuring a fluffy muffin.
In a separate bowl, mash the ripe bananas until smooth. Add the eggs, brown sugar, Greek yogurt, melted butter, and vanilla extract. Whisk together until well combined and smooth.
Pour the wet ingredients into the bowl with the dry ingredients. Gently fold them together with a rubber spatula until just combined. Be careful not to overmix; a few lumps are perfectly fine!
Fold in the chocolate chips and chopped pecans or walnuts. Save a handful of each for topping the muffins before baking.
Spoon the batter into the prepared muffin tin, filling each cavity about two-thirds full. Top with extra chocolate chips and nuts, and sprinkle a little turbinado sugar on top for added crunch.
Place the muffin tin in the preheated oven and bake for 18-22 minutes, or until a toothpick inserted into the center comes out clean. The tops should be golden brown and slightly domed.
Once baked, remove the muffins from the oven and let them cool in the tin for about 5 minutes. Then, transfer them to a wire rack to cool completely. Enjoy them warm or at room temperature!