Have you tried
invoke-nasysstat -Disk *, should give you what you need
TypeName: DataONTAP.Types.Perf.DiskPerfInfo
Name MemberType Definition
---- ---------- ----------
Busy AliasProperty Busy = DiskUtilPercent
DiskRd AliasProperty DiskRd = ReadBytesPerSecond
DiskWr AliasProperty DiskWr = WriteBytesPerSecond
PendOps AliasProperty PendOps = AveragePendingOps
QueueOps AliasProperty QueueOps = AverageQueuedOps
RdLat AliasProperty RdLat = ReadLatency
RdOps AliasProperty RdOps = ReadOpsPerSecond
TotOps AliasProperty TotOps = TotalOpsPerSecond
WrLat AliasProperty WrLat = WriteLatency
WrOps AliasProperty WrOps = WriteOpsPerSecond
Equals Method bool Equals(System.Object obj)
GetHashCode Method int GetHashCode()
GetType Method type GetType()
ToString Method string ToString()
AveragePendingOps Property System.Nullable[decimal] AveragePendingOps {get;set;}
AverageQueuedOps Property System.Nullable[decimal] AverageQueuedOps {get;set;}
Controller Property string Controller {get;set;}
ControllerTimestamp Property System.Nullable[datetime] ControllerTimestamp {get;set;
Disk Property string Disk {get;set;}
DiskUid Property string DiskUid {get;set;}
DiskUtilPercent Property System.Nullable[decimal] DiskUtilPercent {get;set;}
ReadBytesPerSecond Property System.Nullable[decimal] ReadBytesPerSecond {get;set;}
ReadLatency Property System.Nullable[timespan] ReadLatency {get;set;}
ReadOpsPerSecond Property System.Nullable[decimal] ReadOpsPerSecond {get;set;}
Timestamp Property datetime Timestamp {get;set;}
TotalOpsPerSecond Property System.Nullable[decimal] TotalOpsPerSecond {get;set;}
WriteBytesPerSecond Property System.Nullable[decimal] WriteBytesPerSecond {get;set;}
WriteLatency Property System.Nullable[timespan] WriteLatency {get;set;}
WriteOpsPerSecond Property System.Nullable[decimal] WriteOpsPerSecond {get;set;}