Your code contains some mistakes. It should look like this:
Lua Code:
ReshadeMap = {}
ReshadeMap.appName = "ReshadeMap"
local function ReplaceMapTextures(mapId, customTilePathTemplate)
local numX, numY = GetMapNumTilesForMapId(mapId)
local totalTiles = numX * numY
for i = 1, totalTiles do
RedirectTexture(GetMapTileTextureForMapId(mapId, i), customTilePathTemplate:format(i))
end
end
function ReshadeMap.OnAddOnLoaded(_, addOnName)
if addOnName ~= ReshadeMap.appName then return end
ReplaceMapTextures(1290, "ReshadeMap/art/maps/vvardenfell/balmora_base_%d_reshademap.dds")
end
EVENT_MANAGER:RegisterForEvent(ReshadeMap.appName, EVENT_ADD_ON_LOADED, ReshadeMap.OnAddOnLoaded)