NV criminal code, what can I do to contest false accusations of theft from store

Your question was cut off. What you should do depends on whether the manager called police. Did you talk to the police? If what you say is true, then the manager likely saw someone else on the video monitor and mistakenly thought it was you. The danger here is that the police took his report and sent their police incident report to the Prosecutor, who would not know that the video does NOT show you but someone else. It will be cold comfort to be acquitted after you had to hire a lawyer on a false charge, so some early intervention would be wise here.

I do not recommend contacting police or the manager yourself (again?), but someone else on your behalf like a lawyer should ask to see the video. Perhaps it can be shown that it is not really you. The only other possibility is that the manager knows you and has a grudge and is doing this maliciously. I doubt that. The lie is too easily disproved by the video. The ideal situation is for someone to send the police a letter with your photo, full body and head shot, with the explanation that it was not you on the video and the manager accused the wrong person. If the police can be gotten to write a supplemental report and it goes to the Prosecutor with the original, the Prosecutor will want to see the video before he makes any decision on filing charges.

If the police don't want to write a supplemental report, ask to know the report number of the incident, and ask for a form to write a citizen's report supplement to the case. They do this with burglary cases, where you fill out your own report, so maybe you can do it here, but you'll need to put the same police incident report number on yours as the original report.

So get moving. Time is of the essence.