You can make such a flight as you described, but it is not a guarantee. If you plane lands late, you will likely miss the connection. If there is a long wait on the ground before you get to the terminal, you will likely miss the connection. If your incoming flight is changed to another terminal (that does happen), you will likely miss the connection. I would not feel comfortable with the situation that you described. Having the same airline is a plus, so is being at the same terminal, but the Chicago terminals are quite large, and things like delays do happen. Good luck.