If gels make you queasy, the problem may not be the gel — it may be that your gut has never been asked to absorb that much carbohydrate while you run. The capacity to absorb carbs is adaptable, and you can train it.
Start low and build
Begin with a comfortable amount — say 30g/hr — on your long runs, then add roughly 10g/hr every week or two as it becomes easy. Consistency matters more than big jumps.
Practise at race intensity
Digestion at an easy jog is very different from race pace, when blood is diverted to your muscles. Include some goal-pace segments in your fuelled long runs so your gut adapts to the real conditions.
Vary the format
Rotating gels, chews and drink mix keeps things palatable over long days and trains your gut to handle different textures and concentrations. By race week, your fuelling should feel routine, not experimental.