No, a voltage divider is not a solution.
If you have a fixed length of nichrome wire that needs voltage that is less than a multiple of battery cell voltages, a switching buck regulator is a proper solution. Anything less just shortens battery life. Significantly.
A battery is an excellent energy storage device. A capacitor is an energy storage device with significantly less practical capacity than a battery. Using a capacitor to change the effective voltage of the battery is simply the wrong approach. Use a very high efficiency voltage regulator.
Google “buck converter”.