有一个网页说：have been nominated by an employer who is willing to employ you to work full-time in an occupation listed on the Employer Nomination Scheme Occupation List (ENSOL) for at least three years
意思是提供担保的公司要雇用被担保人至少3年。
另一个网页说：have your skills assessed as suitable for the nominated position by the relevant skills assessing authority. A list of assessing bodies can be found in the ENSOL and
unless exceptional circumstances apply, have at least three years full-time work experience in the occupation before the visa application is lodged