Those letters can be used to spell "exigent".
taxwise, waxiest
jovial
sultana
snowday
jetsam
There are three 7-letter words possible:roosterrooterstoreros
Except you gave us 11 letters that spell "celebrating."
Six letter words using the letters 'nuspiegn' are ensign, supine, and genius.
Breeder is a 7 letter words using only those letters
Using all 7 letters you get rewords
You can not spell any 4 letter words with the 3RD letter N using only the letters pmhlijkssxt. The letters do not include the letter N.
'PROSCENIUM' itself is the only 10-letter word using those letters. There are several 8-letter words, but no other 10-letter ones.
Here are some four (4) letter word using the letters, mighuesn: menu. smug. mien. mine. muse. semi. sing. sign. sung. hems. hung.