Here is another method which gets the NomProcess node immediately following the IdProcess node of the value that you specify

DECLARE @xml XML

SET @xml = '<Status>

<IdStatus>1</IdStatus>

<NomStatus>Status 1</NomStatus>

<IdStatus>2</IdStatus>

<NomStatus>Status 2</NomStatus>

<IdStatus>3</IdStatus>

<NomStatus>Status 3</NomStatus>

</Status>

<Process>

<IdProcess>3</IdProcess>

<NomProcess>Process 3</NomProcess>

<IdProcess>2</IdProcess>

<NomProcess>Process 2</NomProcess>

<IdProcess>1</IdProcess>

<NomProcess>Process 1</NomProcess>

</Process>

'

DECLARE @NodeValue INT = 3

SELECT @xml.value('(/Process/NomProcess[ . >> (/Process/IdProcess[text() = sql:variable("@NodeValue")] )[1] ])[1]', 'VARCHAR(100)')