What state do you live in?
The community college -->state university route might be the most cost-effective way to attend college directly after high school.
If you are working full time as a nurse, you may find it difficult to enroll in and take college coursework you’ll need to apply for medical school.
Plus science classes you take for your nursing degree won’t be accepted as fulfilling med school admission requirements.
Psychiatry is medical specialty that requires completing a bachelor’s degree (plus all med school pre-req classes) plus 4 year of medical school, followed by 4 years of medical specialty training (called residency). It’s a long haul.