Your NOVA salary will start out this cheap, but once you complete your training and probationary period, you'll start to receive a ~20,000 yen "regularity" allowance and a few other salary boosts. Additionally, you can start applying for contract performance reviews twice a year, at which time you can earn around 5000 yen increase to your monthly salary. NOVA also covers your travel expenses. In your area, there is also plenty of opportunity for overtime as well.
The management of NOVA schools varies a lot from region to region, and some managers are incredibly bad, and that's why you'll find a lot of negative reviews about the company online. You should have a better time of things in your area. Also, look at the age of the review, because NOVA went through a very ugly bankruptcy about 6? years ago. The current company bought the NOVA trademark and is managing the schools in a much different way than it used to be done.
Expect a lot of travel time though, because the distance between schools in your area is pretty substantial. You'll be better off if you can get a small 250cc motorcycle to commute. On a small motorcycle, you'll be able to travel between schools much more quickly and incredibly cheaply. It's better than a car because you won't need to purchase a parking spot, and you'll be able to park for free at your destination as well. Furthermore, NOVA has no process in place for calculating travel expenses for motorcycles so you can simply claim train fare instead, which in your area will be far more than what it costs to travel by motorcycle. On the other hand, NOVA does indeed have a process in place for calculating travel expenses by car. With a 250cc motorcycle, there's no inspection fee (every two years) either, which can run up to 200,000 yen. Obvious downside to the motorcycle is the weather, but up to a certain point, most of that can be taken care of with the right gear.
Most jobs are not perfect, and don't expect this one to be, nor will it be the best job you'll ever have, but it's no bad.