According to the CPT manual, a 99211 is an office or other outpatient visit "that may not require the presence of a physician. Usually, the presenting problem(s) are minimal. Typically, five minutes are spent performing or supervising these services." Unlike the rest of the office visit codes, 99211 does not have any documentation requirements for the history, physical exam or complexity of medical decision making.
The cost to standardize nursing documentation is minimal: a few copies of a form per year.
None of these visits requires the presence of a physician in the exam room (although the physician should be on the premises). In fact, as a rule of thumb, a physician should not code a 99211. What these visits do require is supporting documentation, so if you plan to charge for nurses' visits, you need to train your nurses to provide very basic medical documentation. I have found the most successful method for achieving adequate and consistent documentation from nurses is to make simple, check-box-driven forms, which guide nurses' decision making, protect you from litigation and give you the clinical data you would want yourself.