There are some countries that offers insurance on the bank that a customer may use. An example of this will FDIC for the US bank networks which protects each account up to $250,000. This is not realistic in Kaldus because there is only one bank. To put asset limits on the account will limit how wealthy a citizen can be. Keep in mind, there is no physical cash, so the citizen does not have any option other than use the banking network for their money.
With that said, there is no limit on deposits, nor will KNB charge for any additional insurance. Since KNB is backed by the national government, there will be as much trust in the bank as there is in the national government network. One could theoretically have $1,000,000,000 with no issues.
Since KNB is a Kaldan business entity, anyone wishing to open an account with KNB must have an NIN and GAON. This requires that the person has a GIN which will depend on whether the person lives in the nation, or outside of the nation. You can learn more about Foreign GINs at the NSC Requirements for Identification.