The phrase "chunky side" refers to a person's weight or body shape that is not slim or thin, but instead on the larger or heavier side. Full definition
I tend to make soups on the thick, chunky side as that is how I like them. (eatgood4life.com)
A deeper front bumper is added, with winglets on its leading edges, along with chunkier side skirts and a compact rear diffuser with two round exhaust pipes either side. (autoexpress.co.uk)
The downside is that it is a bit on the big & chunky side so the Sport won't be comfortable for most people, though. (techguysmartbuy.com)