Read our guide to working in Portugal for a start. As an expat, your income tax will be different than residents, and most expat tax is capped at 20%. This article also explains more about tax for expats in Portugal.
You can also have a look at our page on cost of living for Portugal to see whether taking the job will be worth it or not. Ultimately, the choice remains yours, but generally, the standard of living in Portugal is good and the quality of life is even better. Where are you living right now?
Hope this helped,