From Coleridge's "The Rime of the Ancient Mariner":
The Wedding-Guest sat on a stone:
He cannot chuse but hear;
And thus spake on that ancient man,

I don't remember seeing "chuse" before. Is it a typo,
or a valid obsolete spelling?

COED has an entry for it, calling it a variant of choose. The entry for choose, however, lists it as an earlier spelling, rather than a variant, existing sporadically in ME, but more common in the 16th century.