When you form an LLC in Nevada, you're asked whether the entity will be Member-Managed or Manager-Managed.
The owners of the LLC are called "members." As owners, members have broad discretion to run the company any way they see fit, restricted only by terms outlined in an operating agreement. For Member-Managed LLCs with no operating agreement, the members can do pretty much anything they please with the company. This is one of the many reasons you should have an operating agreement.
If you plan to appoint someone who isn't an owner to handle the day-to-day affairs of the company, you should form a Manager-Managed LLC. Unlike a member, the manager has no automatic ownership interest in the company and the manager's authority to operate the company can and should be restricted in an operating agreement.