The Department of Education's Civil Rights Data Collection periodically publishes data on the racial make-up of students taking AP classes in districts around the country.
In 2017, the data for the Nashua School District showed that both white and Asian students were over-represented in AP courses. You can see this in the data below because the right-hand column is larger than the left-hand column, indicating that these students are more common in AP courses than they are in the overall student body.
Black and Hispanic students, meanwhile, were under-represented.