In 1NT count your winners. Spades:1, Hearts:3, Diamonds:0, Clubs:0. You need to develop winners in clubs before the opposition play diamonds otherwise you are off.
The opponents make 2S, you can't do anything about it. But you only lose 80 points
The Play
It doesn't really matter how you play this in 1NT you are always going light.
Comment
If you are in 1NT you go light losing -100 points.
With the opposition in 1S and making it you only lose -80 points
The above commentary is intended as a guideline only. As with any Bridge hand there are many ways to bid and play any hand.