Decomposed nested components one level. In robofont, obvs.

nested-decompose-selected-glyphs.py

f = CurrentFont()
for g in f.selectedGlyphs:
    if len(g.components) > 0:
        with g.undo('Nested Decompose ' + g.name):
            for component in g.components:
                baseGlyph = f[component.baseGlyph]
                if len(baseGlyph.components) > 0:
                    pen = g.getPointPen()
                    baseGlyph.drawPoints(pen)
                    g.removeComponent(component)
                else:
                    component.decompose()