Expression.Error: We couldn't parse the input provided as a Time value.

esero88 , Try using below code

let
Source = MesaiFact,
#"Added Custom" = Table.AddColumn(Source, "Yesterday", each [Day] - #duration(1,0,0,0)),
#"Changed Type" = Table.TransformColumnTypes(#"Added Custom",{{"Yesterday", type date}}),
#"Converted MinGiris to Time" = Table.TransformColumns(#"Changed Type", {{"MinGiris", each try Time.From(_) otherwise null, type time}}),
#"Inserted Merged Column" = Table.AddColumn(#"Converted MinGiris to Time", "DateMinGiris", each Text.Combine({Text.From([Day], "tr-TR"), Text.From([MinGiris], "tr-TR")}, " "), type text),
#"Merged Queries" = Table.NestedJoin(#"Inserted Merged Column", {"Yesterday", "Card_Number"}, MesaiFact, {"Day", "Card_Number"}, "MesaiFact", JoinKind.Inner)
in
#"Merged Queries"

This error is caused by Time.From, which cannot recognize time with date. If you only need the time, you can use the following code instead of Time.From()

DateTime.Time(DateTime.From("2024-02-21 08:31:05"))