"Charlie Chan in Reno" will probably be on the next DVD set from Fox. Until that time, the only way to have access to "Reno" is through the "grey market" sellers who offer unauthorized copies of Charlie Chan material. Often, their product was recorded from television broadcasts of Charlie Chan movies either on the Fox Movie Channel (2003 and earlier) or American Movie Classics (2000 or earlier).
Again, you can expect 20th Century-Fox to release "Charlie Chan in Reno" in the fairly near future along with the rest of their Chan films.