There are so many variations and it varies by the type of nonprofit you work for, but I can share with you my org's org chat and what I find most nonprofits use in my field of work:

• Executive Director
• Deputy Director (there can be multiple deputy directors but would not recommend if your org is not large)
• Director (usually department heads; can have varying titles from associate director, assistant director, senior director, etc. but would not recommend if your org is not large)
• Manager (usually program managers, people who supervise others, or people who just do a lot of work; can have varying titles like senior manager)
• Specialist (usually for people who can specialize in a technical skill/program/has specialized knowledge)
• Coordinator (usually 1-2 years+ of experience, depending on org)
• Associate/Assistant (entry level)

But it's so subjective depending on the type of work you do. Depending on the industry you work in, this will look different. For example, in the world of foundations/grantmaking, you will find organizations have "Program Officers". Other nonprofits can be very business-like and use "President/CEO" instead of ED and use "Vice President" positions in place of directors, and so forth.

Finally, some universal positions at nonprofits are:

• Finance staff (depending on how big you are, you need somebody to take care of the finance/accounting functions of the org. Some orgs can't afford this so, at first you might just need a bookkeeper and maybe you can hire a business manager at some point)
• HR and operations staff (most orgs don't have this in the beginning and hire someone if they have the ability to)
• Program staff (same as above)
• Fundraising staff/Development Director (self explanatory)
• Executive/management team

What type of nonprofit field are you looking into?