As the others have said: it's little more than an ornament.
Numista's catalogue isn't complete or perfect, especially when it comes to things like this which are issued by a for-profit private “mint” rather than a national mint.
These types of things are churned out at such speed its near impossible to keep up, but also on because they hold so little interest to most collectors, there's little incentive for people to add them into community built sites like this one.
For silver “coins” produced under the authority of Niue, Numista has over 550 known designs for 2022 alone. Imagine how many we don't know about, like yours.
Is it rare, yes probably. These private “mints” often produce them in incredibly low numbers.
However, rare does not mean valuable. It's only valuable if people want it, and as I say, these mints churn out loads of designs a year. Is that design desirable? Who knows.
Probably not, otherwise you'd probably find someone offering it for sale.
It does of course have intrinsic value being 1oz silver, so you should at least get around that value for it if nothing else.
If you want more information on the coin, maybe see if you can find out which mints nominally operated in Nuie for that year or look for ones which might have formed part of a series. Then contact that mint, they might have some records to give you more detail.
Hope you enjoy your visit to Numista. Always feel free to ask questions - we'll do our best to answer them (eventually… 😛).