You need to contact the state CNA registry. You can also wait to receive an application by mail which the state will send you 2-3 months prior to license expiration.
Your Nevada Nurse Aide license is good for 24 months from the date of your last renewal.
Providing you have not become inactive (this means you have not worked a CNA for OVER 2 years), there is a $50 renew your Nevada CNA license. Additional fees apply for inactive status on the State Nurse Aide Registry