No, they're not. I wear Chinos and I'm not remotely a chav. It depends entirely on your taste in clothes though, but I do think some chinos looks worse than others. Carrot trousers (which are like harem pants for guys) and twisting ones get called chavvy but I wouldn't even support that cos I know a lot of preppy / indie people that like those styles. I think the thing is that some of the more ridiculous styles can look a bit pretentious or make you look like a man slag if you're wearing them with low-cut t-shirts to show off your fake-tanned pecs and have one diamond stud in your left ear. See Geordie Shore for details on how this style has been taken over by chavs. But look to Jack Wills to see how the preppy ones wear chinos. And Topman for Hipsters and Indie kids.
At the end of the day, unless you're trying to achieve a certain look, you just borrow from a variety of styles and it's all good. I think Chinos suit a lot of people so it's a good look, and a bit more interesting that everyone wearing jeans.