Move to USA. Portuguese nurse and professional soccer sports.

Good luck on your move to USA. Unfortunately when it comes to jobs in Belize the easy answer is there are none available to expats.  Opportunities include start your own business, or Buy an existing one.

Ohh... thats not what I have on mind yet... Because in Portugal is to hard living nowdays

Well In Belize the minimum wage is $3 to 3.5 bze dollars an hour, that is  $1 to  $1.65 us so less than $100 us per 40 hour week. There is High unemployment, and jobs are always offered to Belize citizens first.
Depending on your lifestyle it can easily be no lower than Portugal., often higher.  local seasonal fruit and vegetables, chicken and pork (Fish and seafood if near the coast), are reasonably cheap any thing imported  (most everything else) is going to be higher  than Portugal.
Housing rentals can range from low(small house few Luxuries} about $300 to 5 hundred a month to Well over $1000 for a more western/european house. It also depends very much on area as in places near the Beaches and on the Cayes the Low prices are often $1000 a month or more.
Not trying to put you off but you asked about opportunities well without an amount of cash to come here with the opportunities are very limited.
I adore it here but we am not needing to work to bring up a family  That we have already done . We have been returning to Belize for nearly 30 years whilst living and working, elsewhere, before deciding now was the time we could really return and live here full time again. Using savings over the last many years to enable land purchase and to build a house, and with pensions to live on.
The Majority of Expats in Belize come in as this older age group. and many of the younger skilled or well educated Belizeans  will go overseas to raise their families if the opportunity ever arises.