This is a tough one! SuperNanny has the answer. Using this technique is not easy. You may have less time and be overly tired because of your long hours at work, school and studies. I think the persistence would pay off in just a week if you can manage it. In the long run it would be worth it.
The first time he gets out of bed put him back in and tell him something like this is your bed now and it's time to go to sleep. The second time out of bed shorten it to bed,sleep. The third time and every time thereafter just put him back in bed. Start out with patience but if he continues to get out of bed be as firm as necessary to get him back in bed.
Nanny was dealing with out of control children but yet it only took the mother a couple of hours or so of doing this the first night. The length of time it took the next few nights became increasingly shorter and within a few days the toddler had learned the lesson. The mother was persistent and consistent sticking with this plan each night and every night in a row.
This is similar to what my daughter did with her son except that she was not consistent or persistent and it took several weeks. Some nights she ignored him and other nights she lectured him so that the process became "attention seeking" and a "battle of wills."
I do think the no nonsense approach in a consistent way would work. It does take patience and the ability to consistently not talk with the toddler. The mothers on SuperNanny had the back up of Nanny. She stayed in the house and coached the mother, the first night, helping her to maintain her cool.
I find it is easier for me maintain my cool when I know that I have a back up. Perhaps a friend could do that for you. Be available, even if only by phone, for you to talk with if you feel yourself getting angry and will start lecturing. You could stop the process long enough to make the call and then go back to it.
At first I didn't understand the no talking rule but then I realized that by not talking the focus is on the staying in bed. The process becomes training with less of a chance of lecturing. And the toddler or child does not get "side tracked" with the words.