JSFiddle - React, Tailwind, and code Playground

JavaScript

sales = {
    obs1: {
        Sales1: {
            Region: "North",
            Value: 200
        },
        Sales2: {
            Region: "South",
            Value: 100
        }
    },
    obs2: {
        Sales1: {
            Region: "North",
            Value: 50
        },
        Sales2: {
            Region: "South",
            Value: 20
        }
    }
}

var totals = {};

function ExtractSales(obj) {
    if (obj.Region && obj.Value) {
        if (totals[obj.Region]) {
            totals[obj.Region] += obj.Value;
        } else {
            totals[obj.Region] = obj.Value;
        }
    } else {
        for (var p in obj) {
            ExtractSales(obj[p]);
        }
    }
}

ExtractSales(sales);

console.log(totals);