Nonprofits are businesses like any other businesses. As such, they have to comply with similar laws.
Your organization should conduct an employment law compliance check. While your organization may have been compliant when it started, changes in the organization can affect what laws apply to you. Local city ordinances may add protected traits to federal and state anti-discrimination laws. A decrease or increase in staff size may change what laws apply to your organization.
Nonprofits are subject to all employment laws in the same manner as for-profit companies. Nonprofits must comply with wage, anti-discrimination laws, and other laws applicable to employers. Not all of these employment laws will apply to your organization since each law has different requirements.