Tax liability of living in a property that is owned by the company you work for

Your question seems to posit that the housing is provided as a benefit and the employee is not charged rent. The value of the housing is likely taxable to the employee:

Unless an exception applies, the full value of the housing is treated as additional taxable compensation to the employee. Full or partial exceptions apply if the housing is:

• Provided for the convenience of the employer
• A temporary work location
• Lodging furnished by an educational institution

For the first part of this answer I am going to ignore the CEO part.

It is very unlikely that the benefit will be tax free.

IRS pub 15-bdescribes what needs to be done to have the fringe benefit not be taxable for the employee: The document is from the view of the employer.

Lodging on Your Business Premises

You can exclude the value of lodging you furnish to an employee from the employee's wages if it meets the following tests.

• It is furnished on your business premises.

• It is furnished for your convenience.

• The employee must accept it as a condition of employment.

Different tests may apply to lodging furnished by educational institutions. See section 119(d) of the Internal Revenue Code for details.

If you allow your employee to choose to receive additional pay instead of lodging, then the lodging, if chosen, isn’t excluded. The exclusion also doesn't apply to cash allowances for lodging.

The document also gives examples.

Then it has one more caveat:

S corporation shareholders.

For this exclusion, don't treat a 2% shareholder of an S corporation as an employee of the corporation. A 2% shareholder is someone who directly or indirectly owns (at any time during the year) more than 2% of the corporation's stock or stock with more than 2% of the voting power. Treat a 2% shareholder as you would a partner in a partnership for fringe benefit purposes, but don't treat the benefit as a reduction in distributions to the 2% shareholder. For more information, see Revenue Ruling 91-26, 1991-1 C.B. 184.

Is the CEO a 2% shareholder? Is the corporation a S corp?

More digging would be needed to understand this additional wrinkle..