I think “digital nomad” tends to refer to remote workers (often working with companies based in their home country) who travel around, “economic migrant” refers to workers moving to a country where there are better job opportunities, specifically to find work at a company based in that country. Less to do with skin tone.
What happens if you move to Germany and draw a salary from a German company for 3 months, then repeat for France, Portugal and Finland? Nomad or immigrant?