Don't have time to make a protein shake? Really? You add 2 scoops to a shaker bottle and then pour in water...
There are a couple problems with chocolate milk.
First, it's high in lactose. Lactose is the milk sugar naturally found in dairy products. The majority of adult humans are sensitive to lactose. This can lead to GI issues like gas and blowing.
Second, it's very high in sugar and very low in protein. A cup of chocolate milk will have around 5g fat, 30g sugar, and only 9g of protein. That is a terrible ratio.
Your best option would be to use a high quality protein shake. You get the beneficial milk proteins, with none of lactose or sugar.
I personally use isolation from n2bm.com. A good whey isolate should be pretty much fat and carb free. Isolation has 26g protein, 1g carb, 0g fat per 30g scoop.
I would use 1-2 scoops of that along with a serving of fruit like a banana.