is it OK to take nytol at night when I
You might experience some drowsiness in the morning after sertraline if you had nytol the previous night. If you are not a physical laborer and if you are not driving during the day, it should be fine to take nytol at night while taking sertraline in the morning.
If you do not want to experience drowsiness, consider avoiding nytol.
Hope this helps. Let me know if you need clarifications.