First of all, I am not immigration attorney or anything like that, but i have read a lot about immigration procedures. Yes, you can be sponsored for a visa by an employer. But you have to have a good relationship with your employer or future employer, and ask him/her/them to sponsor you ( it would be even better and easier if they would offer to sponsor you, of course). Also most likely they (the company) would do all your paperwork. Here's the biggest hurdle: Employment visas or work Visas (they're called something like that) for unskilled workers are very, very hard to get; almost impossible while. It would be much easier if you are college educated with a degree on a field in demand of workers in the country you wish to work in. And yes you would be working in that field/career and with that company to get your visa.
I add to this, if you would like to migrate to Canada. If you get a job offer letter from a Canadian employer certified by Arranged Employment Opinion (AEO) that will definitely improves your chances to migrate to Canada under Skilled Worker scheme, if you fall into any of the 38 occupations list like Auditor, IT professional etc.

For Nigerian, If you have an employer that will sponsor you then contact an Nigerian registered travel agent and they can prepare and lodge the application for you and your employer (at a cost). This is often the fastest and most effective way. They can also give you advice on whether you can get an employer sponsored visa for your occupation. A working example of reliable migration agents are DNA Migration.

Holding to the fact that there are thousands of job seekers out there, wondering if this opportunity won't be rare?.

Yea you are right somany people are seraching for JOB but howmany people are doing the right thing to get them self the Job that they really worth for,most time we settle for a Job due too our Financial difficulties, if you have a good qualification awarded in Nigeria,i advice you apply for a International Professional courses recognized worldwide e.g (CISA, CCNA, OCP/OCA, JAVA  ACCA)and much more, then you have a better chance of applying for Job online and beign given an instant offer.

Thank you for narrowing it this way, as this is more positioned, thus, increasing the chance of inspiring applicant.

This is very good and promising.

Awesome! Its actually remarkable post, I have got much clear idea concerning from this article.

How can I get help to travel to abroad and work there then pay later