Country     metric_count    channel
0   Country1    123472          c1
1   Country1    159392          c2
2   Country2    14599           c3
3   Country2    17382           c4

df2 = df.set_index(["Country", "channel"])

metric_count
Country     channel
Country1    category1   12347
            category2   159392
            category3   14599
            category4   17382

Country2    category1   1234

Country2    top category1   12355555
            top category2   159393
            top category3   16759