Whisk warm milk, yeast, and 1 tablespoon of sugar. Cover and allow it to sit for 5 minutes. The mixture should be frothy on top after 5 minutes. If not, start over with new yeast.
In a separate bowl add 3 cups of flour, salt, plain yogurt, and water. Now, add in the activated yeast mixture, mix to form a dough
Grease some oil on top of the dough and cover it with plastic wrap and keep it at a warm place for at least 2 hours. Let it rise
The dough will double in size after this. Remove the dough into a clean working place, divide the dough into 10 equal balls. Using a rolling pin roll the balls into an oval shape, around 4-5 inches long and ¼ inch thick.
Preheat the air fryer at 350 F Brush some water on top of each naan and sprinkle some nigella seeds and chopped coriander leaves on top. (This step is optional)
Brush some butter in the air fryer basket, place the naan in the basket one at a time and cook for 4 minutes on one side or until little golden brown on top. Do not turn over, cooking on both sides makes the naan hard
Serve hot with your favorite Indian curry or Dal. Brush butter on top of the naan immediately after removing it from the air fryer. Repeat with the rest of the naans.