Others in the same boat will chip in, but only two options seem to be available when it comes to selling:
(a) Stick with the CHESS subregistry but switch to a broker (one from that list) that trades the NSX exchange. Marketech is the only retail online trading platform in the NSX broker list so presumably use them. Steps will be something like:
(1) establish a new brokerage account with Marketech. Make sure it is in exactly the same name as your Superhero account and has exactly the same address details.
(2) Once opened, Marketech will issue you with a HIN.
(3) You can then submit a Broker-to-Broker transfer request form transferring the PRL shares from your Superhero account to your new Marketech HIN.
(4) Once the shares appear over there, upgrade from Marketech’s free plan to a monthly subscription plan for minimum one month (that is, if no free subscription upgrade period is given to you upon new account opening).
Costs of subscription plans and brokerage fees per their website.(5) Sell shares if (big if!) there is a buyer.
(6) Deposit settled funds to your bank account.
(7) Downgrade Marketech back to the free plan, or close the account with them entirely.
or:
(b) Move to Issuer-sponsored subregistry by giving instruction to current broker, Superhero:
(1) Contact Superhero by email or phone and request a transfer of your PRL shares to the “Issuer-sponsored subregistry” managed for PRL by Automic.
(2) To help them process the request, quote your Superhero account/member number, the ticker (PRL), and specify the number of shares to transfer to the Issuer-sponsored subregistry.
(3) After they switch your shares to that subregistry they will advise you of your unique SRN (which is a number in place of a HIN or member number and is used to identify these shares in your name on the subregistry from then on). You might also receive a subsequent letter in the mail from Automic showing the transfer out from CHESS subregistry to Issuer-sponsored (CHESS balance will show as zero for PRL, as it’s gone from your old HIN/Superhero account), plus a letter confirming your new SRN number specifically for these shares on the new subregistry.
(4) View your holding inside Automic’s investor portal and use Automic’s share selling agent to sell your shares on market as a one-off (if there is a buyer). You will quote your SRN for this. The agent they use is sellmyshares.com.au and the
cost of brokerage fees/commissions for the one-off sale is per their website.(5) Deposit settled funds to your bank account.
(6) Buy a Big Mac upsize with the proceeds

Not financial advice, DYOR etc.