A metaphor for a pleasant appearance: perhaps because a supply of chips gives promise of a good fire. (Quot. 1827 is exceptional.)

1

1806.  

        She smiled like a basket of chips,
As tall as a hay-pole her size,
As sweet as molasses her lips,
As bright as a button her eyes.
‘Spirit of the Public Journals,’ p. 115 (Baltimore).    

2

1827.  The Yankee will say of a young lady, “She is a real pretty girl, but she is as homely as a basket of chips.”—Mass. Spy, Nov. 28: from the Berkshire American.

3

1853.  I let him in, as smiling as a basket of chips.—F. W. Thomas, ‘Sketches,’ p. 287 (Phila.).

4

1855.  Mr. Slidell is lying back in his chair, smiling like a basket of chips.—Olympia (W.T.) Pioneer, March 17.

5

1878.  They’ll make up to-night, and she’ll be as pleasant as a basket o’ chips.—Rose T. Cooke, ‘Happy Dodd,’ chap. xxvi.

6

1908.  There he was as smilin’ as a basket o’ chips if he did have to walk with a cane.—Eliza C. Hall, ‘Aunt Jane of Kentucky,’ p. 45.

7