Can a nominee shareholder hide who the real individual with significant control is?

No, at least not legitimately. The whole purpose of the individuals-with-significant-control regime under the Business Corporations Act is to prevent exactly this kind of arrangement from hiding who really controls a corporation. Where shares are formally registered in a nominee's name but someone else actually directs how they're voted or otherwise controls them behind the scenes, the register is supposed to look past the nominee arrangement and identify the real individual exercising that control, not simply record the nominee as the ISC.

Using a nominee arrangement specifically to obscure the true controlling individual doesn't create an exemption from the register requirement; if anything, it can create additional exposure, since knowingly recording inaccurate or incomplete information in the register is treated as a serious compliance failure under the Act, separate from simply failing to update it. Both the corporation and the individuals involved in setting up or maintaining a concealment arrangement can face consequences.

Corporations that use nominee shareholders for legitimate reasons, such as holding shares for estate planning or on behalf of a family trust, still need to trace through to the real controlling individual for register purposes, rather than treating the nominee's name as sufficient.