Error: for a 'var' type a variable needs to be passed

settings.nim

type
    TSettingKind* = enum
        SettingInt, SettingString, SettingChannel, SettingBool
    TSettings = seq[TSetting]
    TSetting* = object
      name*: string

var settings: TTable[string, TSettings]

var newSetting = TSetting(kind: kind)

#Check if key already exists
if settings.hasKey(key):
  settings[key].add(newSetting) #Doesn't work

  #Works
  var existing = settings[key]
  existing.add(newSetting)
else:
    settings[key] = @[newSetting]