I do not know much of anything about Qui Gong. Are there any Qi Gong training exercises that would benefit my Greco-roman wrestling training? Any help would be appreciated.

I'm no expert, only limited experience in the internal arts, but lots of grappling/wrestling experience.

I feel what you will gain are attributes like:

Dynamic balance

Kinesthetic awareness

dynamic relaxation

Knowlegde of your body's relaxation/tension ratio

learn how to control your breath

focus

Qi gong contains a lot of work on your breathing. There is no sport or even physical art that will not benefit from proper breathing. There may be some debate however as to which style(s) of qi gong will give you that benefit.
A good fighter of any style tends to have a little more wind for the latter part of the round and will often use it to impress a judge in sports like boxing.
I'm quite happy with what I get from yiquan which is a kind of qi gong with a martial aspect. qi gong exercises also tend to work toward stretching and relaxation, which might make them good as warm-ups before your regular workout.
Both taiji and yichuan would also give you some tactics that would mix with your wrestling and bagua really makes you flexible.

To build wrestling stamina, cardiovascular workout with prerequisites muscle strengthening of your most utilized joints.

Qigong can help in off days as a recuperative strategy but should not be done in the same day.
You can but the effects are opposite so to make use of the strengths of both, use on different days/rest periods.