While this may be a novel way to cook chicken and you may think it is just for fun...this cooking method actually makes a very tender, juicy chicken.
It can be a challenge to keep the chicken standing upright. The weight of the chicken tends to tip the can over. The easy solution is to use a "Beer Can Chicken Rack" made for this purpose. Several models are available online, ranging from about $5 to $24 (at the time of this writing).
If you do not have a chicken rack you must improvise. You can use 3 small pots, filled with water, positioned around the chicken to keep it propped up. On the outdoor grill you can use bricks or ???.