I graduated from college with a bachelor's in but now I'm in Nursing School am I eligible for American Opportunity Credit I have never claimed this credit before?

Unfortunately, you are not eligible for the American Opportunity Tax Credit because you have already completed your first bachelor's degree.  

However, you may qualify for the Lifetime Learning Tax Credit.  

You are eligible to claim the Lifetime Learning Credit if all of the following requirements are met:

• You (or your dependent or a third party) paid qualified education expenses for higher education.
• You paid the education expenses for an eligible student.
• The eligible student is you, your spouse, or a dependent you claim an exemption for on your tax return.
• Your modified adjusted gross income is less than $67,000 ($134,000 if you are married filing jointly).
• The credit is reduced between $57,000 and $67,000 ($114,000 and $134,000 if you are married filing jointly).

One of the advantages of the Lifetime Learning Credit is that you can take the credit every year for higher education as long as you meet the qualifying requirements.