It's certainly doable, as long as the hub uses a sprocket that can accept 3/32" 'derailleur' chain, rather than the 1/8" thick 'single speed' chain as is commonly used on older IGH bikes. A rear derailleur fixed in one position (with either the limit screws or a short piece of cable) is needed to take up the slack. A two-pulley fixed tensioner will do the same job, but a low-end rear derailleur is far cheaper, especially as it's not being used to shift so quality doesn't matter as much.

The chainrings you should choose depends on what hub you're using. A 3-speed has widely spaced gears, so would benefit from 'half step' gearing. This is where the gears on one chainring fall exactly between the gears on the other. The idea here is that you'd use the hub gears to set the general range, with the front derailleur for fine-tuning. With a triple crankset, 'third step' gearing can be used with the same principle. Hubs with more gears would be better with a larger spacing between chainrings, giving two or three overlapping gear ranges as with a derailleur-equipped bike.

One thing to be careful of is over-torquing the hub. Sturmey-Archer 3-speeds seem to take whatever you throw at them, but other hubs have a maximum sprocket/chainring ratio which limits the low gear range you can get.

While to some extent, you get the drawbacks of both systems, you get some of the advantages too. The ability to shift at least some of the gears while stationary is an advantage when riding in traffic. A bicycle with vertical dropouts and an IGH must generally run a chain tensioner anyway, so substituting this for a rear derailleur is less of a disadvantage.