Common words:
* fashion
* nation
* motion
* publish
* finish
* crash
* flash
* fresh
* push
* wish
* brush
* dish
* fish
* flesh
Less common words:
* abolish
* accomplish
* admonish
* ambitious
* anxious
* conscious
* delicious
* establish
* garnish
* glorious
* honish (archaic)
* nourish
* polish
* prohibition
* relish
* vanish
* wishing
Words with "sh" as part of a larger sound:
* treasure (sh sound at the end)
* pleasure (sh sound at the end)
* measure (sh sound at the end)
* pressure (sh sound at the end)
This is just a small selection, and there are many more words with "sh" in the middle. You can use a dictionary or online search to find more examples.