You just need a charger (power supply) with the same voltage (V) and at least the same number of amperes (A) or power (W) that uses the same plug and polarity (+ and - connections).
For instance (these numbers are examples): if the original charger is 5V and 2A (or 5V x 2A = 10W), you need one with exactly 5V and at least 2A or 10W (if it's 3A or 15W it's OK, it can be more but not less). Of course, check the plug that goes in the tablet to make sure it's the same type and the + and - connectors are the same (usually one is the inside connector and the other one is outside the plug).
I've gone "MacGyver" on the factory charger and spliced the chewed up wires together and got my tablet to charge today. I'll go charger hunting this weekend to try and locate a more permanent solution to my charger woes.