To get the money I was owed by this company I had to hire a lawyer and fight this through the Labor court in Saudi. It will take you months / years to get what you are owed and a lot of that will go to the Lawyer you hire.
Having said that, there are a few Lawyers in Saudi now that know Nexus by name and have won against them. I would be very reluctant to join this company. While the promise of great pay and schedule will draw you in, you can believe that your schedule will change without notice and you will spend every month wondering if you will be paid.
The company operates, in my opinion, as a kind of ponzi scheme. I believe they don't have enough free cash to pay their people or suppliers and when money from one contract comes in they use it to cover another. If you do join this company, insist on being paid upfront / in advance of working for the month. Do not get the resident permit and enter the country under their sponsorship.
They can choose to not issue you an exit visa and you could be stuck in the country for months with no pay and nowhere to live! Hopefully enough prospective crew will see this (and all the other comments) and avoid this company. There are better, more stable places to work.