Ann: ATO Class Ruling Received, page-3

As expected the Nico shares are a capital return that reduces the cost base of MLX and forms the cost base of NIC when multiplied by 36.29 (we got 1 NIC for every 36.29 MLX shares). MLX ann did not provide details of the amounts. They left it to us to look up the ATO ruling. Search link provided for Metals X gets you to;
https://www.ato.gov.au/law/view/pdf/pbr/cr2022-080.pdf

10. If you did not make a capital gain from CGT event G1 happening in relation to your
Metals X share, you reduce the cost base and reduced cost base of your Metals X share
by 1.41479c

11. The first element of the cost base and reduced cost base of each NICO share you
acquired is 51.3437c (subsections 110-25(2) and 110-55(2)).