An employment contract is in fact required in order to get a NISS. This is a recent change. I believe it’s tied to the government’s recent cancellation of the “expression of interest” procedure in June. I’m under 65 and retired, and applied and was denied a NISS since I don’t have an employment contract.
If you or anyone on this platform has obtained a NISS in the last 2 months without a job contract, please provide details: where you applied, what documentation you presented, and any other tips.