The bowler's home ground is hosting the fourth match in the Ashes series.
The 30-year-old told Sky Sports News: "To put an England shirt on anywhere in the world is great, but to potentially have a chance, it's kind of in my hands, to play an Ashes Test on your home ground would be even better.
"It would be great to walk down the steps and take some wickets and beat the Aussies. That's the goal, but if you look too far ahead that can be quite dangerous. It's a little bit of a dream in the future.
"I feel pretty confident, I'm raring to go, I feel fit and strong, and it's just a case of getting that ball in your hand in English conditions, we know it's going to be cold, and dealing with that."
Onions has played in nine Tests for England, taking 32 wickets.