When I try to start my bike I hear a chattering noise

Most likely there is just enough juice left in the battery to actuate the starter relay, but not enough to turn the motor itself. That is your clicking noise. This happens to cars, too. Also check that the screws holding the cables on to the battery are snug. If the battery and its connections are okay then try this:

Get someone more mechanically knowledgable to carefully stick a screwdriver across the starter relay main leads; don't touch the metal part of the screwdriver though. If the motor turns over fine then have them check the starter button itself. If the contacts in the starter button itself are blackened/corroded clean them off. I have seen this happen in other Ninjas. A pencil eraser works well for this. There are many other possibilities but these are three good ones.