1NT is 15-17,
(pd could upgrade 14 with good 5 card minor, and will not have 17 with good 5 card minor)
maybe you have a better system to handle this hand, but suppose your options now are either :
3NT to play
4NT invitational (after which opener , if accepting, can show 4 or 5 card suits)
your choice?

Help

1NT - 2♣
2♦ - ?