You may be in or outside Australia to lodge a valid visa application. There are 3 streams under the ENS stream:
Temporary Residence Transition (TRT)
In general, the eligibility requirements to be met for an Employer Sponsored Visa would be:
Your employer must have applied for approval of the nomination of the position which your visa application relates, and it must be approved.
Depending on the State or Territory where your position is located, it may be that you must hold or be eligible to apply for and hold a relevant licence, registration or professional membership.
You must satisfy required Nomination Criteria for the visa stream you are applying for example holding a specific visa for a specific period, having an occupation on the relevant list of eligible occupations or having been employed in your nominated occupation for a required period of time.