render fiat balances

app/components/hooks/usePortfolioBalance/usePortfolioBalance.ts

@@ -35,6 +35,7 @@ import {
   selectMultichainSelectedAccountCachedBalance,
   selectMultichainDefaultToken,
   selectMultichainShouldShowFiat,
+  selectMultichainConversionRate,
 } from '../../../selectors/multichain';
 ///: END:ONLY_INCLUDE_IF
 
@@ -91,6 +92,7 @@ const usePortfolioBalance = (): UsePortfolioBalanceHook => {
   );
   const { symbol } = useSelector(selectMultichainDefaultToken);
   const shouldShowFiat = useSelector(selectMultichainShouldShowFiat);
+  const multichainConversionRate = useSelector(selectMultichainConversionRate);
   ///: END:ONLY_INCLUDE_IF
 
   // Production balance calculation (EVM)
@@ -121,13 +123,29 @@ const usePortfolioBalance = (): UsePortfolioBalanceHook => {
   };
 
   ///: BEGIN:ONLY_INCLUDE_IF(keyring-snaps)
+  const getMultiChainFiatBalance = (
+    nativeTokenBalance: string,
+    conversionRate: number,
+    currency: string,
+  ) => {
+    const multichainBalance = Number(nativeTokenBalance);
+    const fiatBalance = multichainBalance * conversionRate;
+    return renderFiat(fiatBalance, currency);
+  };
+
   const getNonEvmDisplayBalance = () => {
     if (!shouldShowFiat) {
-      const total =
-        totalFiatBalancesCrossChain[selectedInternalAccount?.address as string]
-          ?.totalFiatBalance ?? 0;
-      return renderFiat(total, currentCurrency);
+      return `${multichainSelectedAccountCachedBalance} ${symbol}`;
     }
+    if (multichainSelectedAccountCachedBalance && multichainConversionRate) {
+      return getMultiChainFiatBalance(
+        multichainSelectedAccountCachedBalance,
+        multichainConversionRate,
+        currentCurrency,
+      );
+    }
+
+    // default to native token symbol
     return `${multichainSelectedAccountCachedBalance} ${symbol}`;
   };
   ///: END:ONLY_INCLUDE_IF