By “venting”, I presume you mean your range hood. If so, *do not* connect that to your chimney flue. That’s a no-no.
To be proper,the range hood must be vented to the outside, although some of them just vent to the attic, as long as it’s well ventialated. I don’t think that’s technically “kosher”, though.
If you mean venting in the sense of venting the byproducts of combustion, guess what? You don’t.
Believe it or not, they simply stay right in your house. Natural gas burns cleanly, and it is not required to vent the stove.
Kinda makes you wonder why the big deal with venting things like your water heater and gas fireplace. No? But that’s the way it is.
I guess the leg they have to stand on is that cooking is limited. You aren’t running all your burner all day long.
Anyway, I’ve had gas stoves all my life, and it’s never been a problem. And prior to this house, none of the ranges even had a hood.
Not only that, some of the range hoods simply filter out the smoke and vent the exhaust directly back into the room.
http://www.dream-kitchen-ideas.com/ductless-range-hoods.html