Combine 1/4 cup flour, brown sugar, 1/4 cup butter, walnuts, pecans, and cinnamon in a bowl until crumbly; set topping aside.
Preheat the oven to 375 degrees F (190 degrees C). Coat a fluted tube pan (such as Bundt) with cooking spray.
Beat white sugar, yogurt, remaining 3/4 cup butter, milk, eggs, baking powder, and salt in a large bowl with an electric mixer until smooth. Slowly mix in remaining 3 cups flour until combined; batter will be thick. Pour 1/2 batter into bottom of the prepared pan; generously spread 1/2 brown sugar-cinnamon topping over batter. Top with remaining 1/2 batter followed by remaining 1/2 topping.
Bake in the preheated oven until a toothpick inserted into center comes out clean, 45 to 50 minutes. Cool on a wire rack for 5 minutes. Run a table knife around the edges to loosen; tap the pan firmly a few times, then shake it gently to loosen the cake. Place a wire rack over the pan and invert to release cake onto the rack, then invert onto a plate, brown sugar-cinnamon-side up.
