My Nike+ sensor recently died and after looking around the web I found that they wanted $20 to replace it! So instead, contrary to what others on the web seemed to say, I took it apart and found the process very simple and it only took 10-15 min. and a $4 dollar battery.
Pliers (optional, but handy)
Small philips screwdriver
Crazy glue (also optional, but handy :-) )
Please feel free to comment and rate! I'd love to hear your input!
Step 1: Disassemble the chip
Use your knife to pry apart the side of the chip. Then use a small screwdriver to remove the 2 screws on the top.