https://loudclouds.co/plant-nutrient-deficiency-chart/
This will give ya something to compare to so that you at least have a reference, it's difficult to give a accurate diagnosis without knowing all your parameters but yes nitrogen deficiency is a possibility or you could have a ph lock out as well and depending on the size of your pots you could flush 3 to 1 with water for the valume of soil..EI 3L to 1L.of soil