Combine the yeast, sugar, and warm water, mixing gently until just combined. Let the mixture rest for 7-10 minutes.
In a separate bowl, whisk together the greek yogurt, milk, and olive oil.
Add the yogurt mixture to the yeast mixture and mix until just combined.
In a separate bowl, whisk together the flour, baking soda, and salt.
Add the flour mixture to the yeast and yogurt mixture. Use your hands or a mixer with a dough hook attached to combine.
On a lightly floured surface, knead the dough for about 6 minutes, or until the dough is smooth and slightly springy but not firm. Then, cover the dough with a clean towel and let it rest for 90 minutes until the dough has approximately doubled in size.
Divide the dough into 8 balls of equal size. Allow the dough to rest for 15 minutes after forming the balls.
Heat a cast iron skillet to medium-high heat. No oil is needed. The skillet should be very hot and dry. Roll each ball of dough to about ¼-inch thickness using a rolling pin and cook for 2 minutes in the skillet until large bubbles form within the dough. At this point, flip the naan and continue cooking for an additional 2 minutes.