Residency in Mexico requires a passport and a Visa (FM2 or FM3) plus special permission on the visa to work at a specific job in a very specific location. The work permission is very difficult, if not impossible to get. There are lots of electricians in Mexico and nurses too. The residency visa will cost about $140 per person to apply, then a similar renewal fee each year. It will also require you to prove about $1200 US per person per month in income from sources outside of Mexico. I don't think your dream is practical. Most of us on these boards are already retired.