Does anyone know where I can obtain OSHA training and certification in Confined Space as an instructor?

Sir, try getting in touch with someone at the Army CBRN school.
https://www.rallypoint.com/units/usacbrns-us-army-chemical-biological-radiological-nuclear-cbrn-school-fort-leonard-wood-mo/current

Maj. Galloway,

I do not know where you reside or are stationed, however the advice that you have been given is pertinent. You should first contact the Regional OSHA office or the applicable State OSHA office, (Federal OSHA is not active in some states and the states have their own OSHA program). You should also contact your local Military Safety Office, they should be able to assist you. You can also contact the OSHA Training Institute in Chicago. OSHA has accredited training programs set up with various Colleges theouought the US. You need to be aware that the Confined Space Program is applicable to both General Industry, (as covered by CFR 1910.146), and Construction, (as covered in CFR 1926, various vertical standards). Be advised that the training is extensive and covers both occupational safety and health standards. If you need their advice or if I can be of any further assistance, please contact me directly.

R. Mark Hickey, former Chief of Vermont OSHA Compliance Programs