Why stop at just the instance name? You can inventory your SQL Server environment with following:
SELECT
SERVERPROPERTY('ServerName') AS ServerName,
SERVERPROPERTY('MachineName') AS MachineName,
CASE
WHEN SERVERPROPERTY('InstanceName') IS NULL THEN ''
ELSE SERVERPROPERTY('InstanceName')
END AS InstanceName,
'' as Port, --need to update to strip from Servername. Note: Assumes Registered Server is named with Port
SUBSTRING ( (SELECT @@VERSION),1, CHARINDEX('-',(SELECT @@VERSION))-1 ) as ProductName,
SERVERPROPERTY('ProductVersion') AS ProductVersion,
SERVERPROPERTY('ProductLevel') AS ProductLevel,
SERVERPROPERTY('ProductMajorVersion') AS ProductMajorVersion,
SERVERPROPERTY('ProductMinorVersion') AS ProductMinorVersion,
SERVERPROPERTY('ProductBuild') AS ProductBuild,
SERVERPROPERTY('Edition') AS Edition,
CASE SERVERPROPERTY('EngineEdition')
WHEN 1 THEN 'PERSONAL'
WHEN 2 THEN 'STANDARD'
WHEN 3 THEN 'ENTERPRISE'
WHEN 4 THEN 'EXPRESS'
WHEN 5 THEN 'SQL DATABASE'
WHEN 6 THEN 'SQL DATAWAREHOUSE'
END AS EngineEdition,
CASE SERVERPROPERTY('IsHadrEnabled')
WHEN 0 THEN 'The Always On Availability Groups feature is disabled'
WHEN 1 THEN 'The Always On Availability Groups feature is enabled'
ELSE 'Not applicable'
END AS HadrEnabled,
CASE SERVERPROPERTY('HadrManagerStatus')
WHEN 0 THEN 'Not started, pending communication'
WHEN 1 THEN 'Started and running'
WHEN 2 THEN 'Not started and failed'
ELSE 'Not applicable'
END AS HadrManagerStatus,
CASE SERVERPROPERTY('IsSingleUser') WHEN 0 THEN 'No' ELSE 'Yes' END AS InSingleUserMode,
CASE SERVERPROPERTY('IsClustered')
WHEN 1 THEN 'Clustered'
WHEN 0 THEN 'Not Clustered'
ELSE 'Not applicable'
END AS IsClustered,
'' as ServerEnvironment,
'' as ServerStatus,
'' as Comments