First, that's a terrifically broad question. Compensation would include lost wages following what would otherwise have been a return to work, and possibly some incidental expenses, but it's very fact-dependent. The settlement may also be affected by whether the employee wants to be reinstated. If so, a common settlement is reinstatement with back pay.

Second, it's important to keep in mind that a right to sue letter is not a statement that a case has merit. The mere fact that a letter was issued does not mean that the Department of Labor concluded either that the claims are meritorious or that the employee is likely to win a lawsuit.

If the employer is denying any responsibility to reinstate the employee, or if they have offered reinstatement with back pay and the employee wants more or prefers not to return, the employee should consult a plaintiff-side immigration lawyer for a review of the merits of the case and an impression of what a reasonable settlement might be.