I am not a Nevada lawyer. I know nothing about Nevada employment laws. But, if Nevada is anything like Ohio, workers' compensation is employee's exclusive remedy for any injuries an employee suffers related to work, and an employer would be immune from any other injury claims.
Moreover, in Ohio, an employee cannot preemptively waive a workers' compensation claim. Which means that if Nacho Daddy was an Ohio employer, its waiver document would be null, void, meaningless, and unenforceable.
It also makes for really bad employee relations. What message do you send to your employees if you ask / require them to promise not to file a claim against you if they become ill with COVID-19 after they return to work? It tells them that you only care about your bottom line, and couldn't give two you-know-whats about them as employees.
Instead of wasting time, effort, paper, ink, and employee morale fostering enforceable waiver agreements on your employees, spend the time communicating to them everything you will be doing to help ensure their health and safety when they return to work. Make them comfortable with your return to work plans. Let them know that you are doing everything that the state requires you to do to reopen, and then some. Don't force them to return to a workplace they feel is unsafe to work for an employer they feel is uncaring. Instead, have them return happily and voluntarily to a workplace that cares about them and their wellbeing.
The waiver Nacho Daddy is requiring its employees to sign is fostering an "us vs. them" mentality. The battle against COVID-19 will be won with an "us vs. them." It will only be won with a "we." So let's try and focus on the "we" instead of dividing us with silly endeavors such as unenforceable waiver agreements.