Nardo di Cione colour palette is showing blues and gold. Read here for the meaning of these and other colours in medieval art.
"Nardo di Cione, (active 1343 — ca.1365), was an Italian painter, sculptor and architect from Florence. He was the brother of the more accomplished Andrea di Cione, called Orcagna, as well as Jacopo di Cione; they were important members of the Painter’s Guild of Florence. While Orcagna has been noted as the more accomplished artist, Nardo developed his own unique style, described as “a pronounced lyrical vein, a feeling for poetic values, strong human sympathies and great sensitivity to colour as a means of subtle differentiation and soft modeling".”
Medieval Art Colours, techniques and symbolism of medieval artists