Charging system warning light and brake warning light being on simultaneously is consistent with a charging system problem (Nissan's have been designed like that for decades). Loose battery cable connections are pretty common on these vehicles, especially when an aftermarket battery is installed, so make sure you can't turn the cables on the battery posts by hand and also make sure they are clean. Also, the regulator is controlled by the ECM based on input from a voltage sensor on the negative battery cable, so, if you have any aftermarket additions, make sure they are not grounded at the battery post or between the post and the voltage sensor; they should be grounded to the chassis.
A good charging system will charge between 13.2-15.5 volts at idle and at 3000 RPM, both with "loads" (headlights, heater, etc.) on and off. If the battery tests good, the connections are good but the voltage is not within spec, chances are your alternator is faulty. If you can afford it, it's best to stick with a genuine Nissan part.