Is there a way for me to reset my tank average without actually filling my tank on my non-Nav TCH?

Thanks,
Scott

Disconnect the battery? Just a guess.

2008 Barcelona Red Metallic TCH Mods: 20% hybrid window tint, Wade window vent visors, lower grill chrome accents, fog lights, factory spoiler, Razzi ground effects, Razzi simulated dual exhaust

To what benefit?
The tank average is only an approximation based upon a short stretch of driving.
The true fuel economy indicator is the calculations over an extended period of time, such as a few months or even a year, so that you woul average in the various temperatures, driving distances, etc.
Over a short term, like half a tank or even less, would indicate...essentially, a non-sense figure.
My MPG meter shows 99MPG by coasting down a hill for 1/2 mile after filling up the tank, but what does that indicate?

Ssummers may be trying to check the mpg between two points without having to fill up.

I had a new Ford a few years ago with a digital mpg readout. I could press the mpg reset and that made it easy to see your rather accurate mpg between cities of about 80 miles apart. Any shorter distances it would read a inaccurate high.

The TCH only resets when you fill the tank.

Not sure, but when the fuel door is open and the cap removed, the system resets.
Does it reset because the door is open, or does the system reset because it detects that fuel is being added?
Maybe try removing the cap for a few seconds and see if it's the because the cap is off?