For most college classes, the number og credits is an approximation of class hours per week. Nursing and other lab classrs are calculated very differently.
Also, as a general rule in education, each credit hour should account for approximately 3 hours of study. So your 3 credit intro to psych should take 9 hours a week. However, most of my general education classes took much less time. Nursing classes on the other hand, require much more than 3 hrs/credit. There are also other components to classes that are not part of the schedule. Fot example, tutorials, labs, and tests might not be during your scheduled class time. You might also be required to go to clinical early or in advance to get your assignment.
Be very careful to factor in time for sleep, relaxation, and travel.
In general, you should expect being a (full-time) student in an RN program to be at least the equivalent of a full-time job (i.e., ~40 hours/week). As rakcna noted, the actual number of class and clinical hours is just "the tip of the iceberg." There will be lab hours, tutorials, clinical prep time, and who knows what else, that will not be reflected in the number of hours "on paper," plus the time needed to study.
Here's my schedule next semester: tues- lecture 8-10, Wednesday- lecture 8-11, Thursday- clinicals 6am-6pm, Friday- clinicals 6am-6pm. Paperwork for clinicals are due Tuesday. So I spend the weekend doing paperwork and studying. It's not impossible NOT to work. I'd just suggest part time. However, if you're also taking other classes along with nursing classes, I'd suggest not working. I want to work part time too but risking failing nursing school because I wanted a few extra bucks isn't worth it for me.
My own schedule last semester was something like this: Tuesday: class 8:00-12:00. Study until about 5 pm, and then after about 8:30-10:00.
Wednesday: Class 7:30-10:00. Clinical Prep 12-3. Work on care plan until about 5 pm. Then again from about 8:30 - 10:00 pm.
Thursday: Clinical 6:30am - 2 pm. Go to work from 3-11pm. Tweak care plan at work and possibly as late as 2 am. Friday, same as Thursday.
Saturday: sleep in a little, study until about 11 am. Family time until about 1 pm. Free time for about an hour, Work 3-11 pm. Study some while at work. Sunday is repeat of Saturday.
Monday: Take kid to school - 7:45. Study until about noon. Free time until around 1:30, or attend any extracurricular meetings, then work from 3-11pm and study while at work some.
Yes, that's basically what my schedule was. Next semester will be similar. The first week will be a blur. After that, things will all flow together and before I know it, the semester will be over... and then on to 4th semester.
Also, any job you have will need to be fairly flexible -- your school schedule will change from semester to semester, and you will sometimes have unexpected school commitments outside the standard schedule, school schedules can be changed on fairly short notice, you may need extra time to study for an exam or finish a paper on a deadline, etc.
When I attended an LPN-to-RN completion program, my school hours were:
Classroom (theory) - Tuesdays and Thursdays from 1:00pm to 5:00pm
Clinical practicum - Wednesdays from 6:00am-2:00pm or 2:00pm-10:00pm
Throughout the program I worked weekend double shifts as an LVN in a nursing home. I worked from 6:00am to 10:00pm every Saturday and Sunday. This schedule ensured that I had Monday through Friday off to focus on school.