We want to promote an employee to a new position we’re creating. Do we need to give other potential candidates the chance to apply as well?
It depends. If you have an established company policy that promises a practice of posting internally, you should follow this. But, generally no, you’re not required to post for it. Only federal contractors are required to post open positions, so you can offer the employee the job without posting it for potential external or internal candidates to apply.
I do recommend at least posting new positions internally, as it shows transparency and increases the likelihood of finding the best candidate. The employee you had in mind might not actually be the best person for the job, they may not be interested in the position, or other circumstances might change such that having a wider applicant pool would be an advantage. Posting jobs internally also helps you keep a pulse on your internal talent pool and see who is interested in either cross training or promotional opportunities.