Tourist taxis - Are blue and rates are fixed depending on destination.
Basic taxis- Are metered and are colored black and yellow.
For tourist taxis, you can order for one at the taxi counter near the baggage claim area just before entering into the arrivals sitting area in either of the two terminals. There's also a system at the airport known as via controlada that enables tourists using tourist taxis to know the fares to various destinations across Santiago.
Once you cross the gates and are the arrivals arena, basic taxi drivers are always wandering about looking for tourists, they usually overcharge unsuspecting tourists who are not aware of the existing currency rates in Chile.
The best thing to do is to avoid them completely, avoid approaching them to ask about transport or fares as that alone can make them follow you around.