/setblock ~0 ~1 ~0 minecraft:chest 0 replace {Items:[{id:minecraft:banner,Count:1,Slot:0,tag:{BlockEntityTag:{Base:15,Patterns:[{Color:5,Pattern:bri},{Color:4,Pattern:gru},{Color:5,Pattern:gra},{Color:5,Pattern:bri},{Color:15,Pattern:bo},{Color:15,Pattern:cbo},{Color:15,Pattern:bri},{Color:15,Pattern:ss}]}}},]}