EXAMPLES FROM THE WEB FOR CHAW
I tell ye what you do: Give him a bone or a chunk of tough meat to chaw on.
“Might chaw on a biscuit before I take another nap,” yawned the prisoner.
Ain't you afraid that you might take a chaw on it, by mistake for your tobacco?
Then he inquired as an afterthought: “Would he snap or chaw me up a-tall?”
Not so much as a chaw of bacon, or a blanket to lay over you nights.
An' I'm hungry 'nough to chaw grass, were you to show me a tidy patch an' say go to it!
I'm that near gone I could chaw on a dog biscuit and like it!
Then Tom was fond of a chaw, and seldom had had a quid out of his cheeks.
But if that is the case why did he interfere whin the grizzly was about to chaw me up?
Maybe Bill he gives him a chaw; maybe he lies and says he ain't got none.
1520s, unexplained phonetic variant of chew (v.). OED points out the variant form chow was "very common in 16-17th c." Bartlett's "Dictionary of Americanisms"  says chaw, "Although found in good authors, ... is retained, in this country as in England, only by the illiterate." Related: Chawed; chawing. The noun meaning "that which is chewed" (especially a quid of tobacco) first recorded 1709.