Been there. No food recommendations.

If you make the trip to see the Terracotta Army, plan on the trip taking twice as long as the hotel concierge tells you. The traffic is TERRIBLE.

There's a Walmart near the city wall that's pretty cool - if you've never been in a Chinese Walmart. You could get the ingredients for an authentic Chinese meal there.

If you go to Chengdu to see the Pandas, I recommend having pizza at this restaurant: Mike's Pizza Kitchen | Chengdu | Delivery, Take-out, Dine-in (honestly; check the Tripadvisor reviews)