Make a video. Use your phone, iPod, or other device and record your toddler doing just about anything - singing, talking, dancing, and so forth. Toddlers love to watch themselves, so if you teach him how to press play and how to hold the phone (or whatever it is), you'll have some quiet and uninterrupted time to nurse.
Read. Ask him to bring you some books, and then let him turn the pages while you read them to him. After a few books, he might be content to just sit next to you and flip through them quietly on his own.
Puzzles. Any kind of puzzle works, as long as it's not too difficult for him to manipulate the pieces and figure out how to fit them together.
Scavenger hunt. Ask him to find things, such as specific toys (Buzz & Woody) or other items (orange blanket).
Cups. Dump a bunch of plastic cups on the floor nearby. Ask him to help pick them up or tell him he can play with them. Soon he'll be focused on stacking them or nesting them or stepping on them to make them make noise or something completely different altogether.
Beach ball or balloon. Kids love them. Hand him one and let him go nuts trying to keep it up in the air and off of the floor.
Clothes pins. Stretch a piece of yarn from one side of the room to the other, such as from the crib to the changing table. Give him a small bowl of clothespins and any piece of paper or other item he can hang up - old magazine pages, pictures he's colored, and so forth. Show him how to hang things from the yarn and he'll go to town with it.
Information taken from: http://thedizzymom.blogspot.com/2012/09/10-ways-to-keep-your-toddler-busy-while.html