Every course requires a different amount of effort, just as every student has different needs when it comes to learning new material. Until you get up to speed in a new graduate course it’s good to err on the side of caution. Set aside more study time each week to start, even if you think you’ll use less. Also take a look at the syllabus and assignments and adjust accordingly.
For graduate nursing education courses, 10 hours of dedicated study time per week is a good place to begin. If major tests, research papers or presentations lie ahead, give yourself a few extra hours to study and complete assignments during those weeks. Once you have taken a few courses, it will be easier to gage what works best for you.